public static void loadRelocations(BinaryIn source, CoffSection sec, Win32Obj objfile)
{
source.seek(sec.relocTblPos);
for (int i = 0; i < sec.relocTblCount; i++)
{
uint addr = source.getFour();
int symidx = (int)source.getFour();
uint reloctype = source.getTwo();
CoffRelocation.Reloctype reltype = CoffRelocation.Reloctype.NONE;
switch (reloctype)
{
case 06:
reltype = CoffRelocation.Reloctype.ABSOLUTE; //IMAGE_REL_I386_DIR32
break;
case 07:
reltype = CoffRelocation.Reloctype.RVA; //IMAGE_REL_I386_DIR32NB
break;
case 11:
reltype = CoffRelocation.Reloctype.SECREL32; //IMAGE_REL_I386_SECREL
break;
case 20:
reltype = CoffRelocation.Reloctype.RELATIVE; //IMAGE_REL_I386_REL32
break;
default:
break;
}
CoffSymbol sym = objfile.symbols[symidx];
CoffRelocation reloc = new CoffRelocation(addr - sec.memPos, sym, reltype);
sec.relocations.Add(reloc);
}
}
public static void loadSymbols(BinaryIn source, uint count, byte[] strtbl, Win32Obj objfile)
{
for (int i = 0; i < count;)
{
//get short name or pos in string tbl
uint nameloc = source.getPos();
uint namezeros = source.getFour();
String name = "";
if (namezeros == 0) //if first 4 bytes = 0, 2nd 4 bytes = ofs into str tbl
{
int namepos = (int)source.getFour();
name = readString(strtbl, namepos);
}
else
{
source.seek(nameloc);
name = source.getAsciiString(8);
}
//read rest of sym entry
uint val = source.getFour();
uint secval = source.getTwo();
uint type = source.getTwo();
CoffStorageClass storage = (CoffStorageClass)source.getOne();
uint aux = source.getOne();
CoffSymbol sym = null;
CoffSymbol.SYMBIND bind = CoffSymbol.SYMBIND.EXTERNAL;
uint size = 0;
uint addr = 0;
CoffSection sec = null;
switch (storage)
{
case CoffStorageClass.IMAGE_SYM_CLASS_EXTERNAL:
if (secval == 0)
{
if (val == 0)
{
bind = CoffSymbol.SYMBIND.EXTERNAL;
}
else
{
bind = CoffSymbol.SYMBIND.COMMON;
size = val;
}
}
else
{
bind = CoffSymbol.SYMBIND.GLOBAL;
sec = objfile.sections[(int)secval - 1];
if (val >= sec.memPos)
{
addr = val - sec.memPos;
}
}
sym = new CoffSymbol(name);
sym.bind = bind;
sym.typ = CoffSymbol.SYMTYPE.FUNCTION;
sym.section = sec;
sym.ofs = addr;
sym.size = size;
break;
case CoffStorageClass.IMAGE_SYM_CLASS_STATIC:
case CoffStorageClass.IMAGE_SYM_CLASS_LABEL:
if (secval != 0xffff)
{
sec = objfile.sections[(int)secval - 1];
if (val >= sec.memPos)
{
addr = val - sec.memPos;
}
sym = new CoffSymbol(name);
sym.bind = CoffSymbol.SYMBIND.LOCAL;
sym.typ = CoffSymbol.SYMTYPE.FUNCTION;
sym.section = sec;
sym.ofs = addr;
sym.size = size;
}
break;
case CoffStorageClass.IMAGE_SYM_CLASS_SECTION:
sec = objfile.sections[(int)secval - 1];
sym = new CoffSymbol(name);
sym.bind = CoffSymbol.SYMBIND.LOCAL;
sym.typ = CoffSymbol.SYMTYPE.FUNCTION;
sym.section = sec;
sym.ofs = addr;
sym.size = size;
break;
case CoffStorageClass.IMAGE_SYM_CLASS_FUNCTION:
case CoffStorageClass.IMAGE_SYM_CLASS_FILE:
break;
default:
break;
}
i++;
objfile.symbols.Add(sym);
if (sym != null)
{
objfile.symNames[sym.name] = sym;
}
//skip any aux sym entries
for (int j = 0; j < aux; j++)
{
source.skip(CoffSymbol.SYMTBLENTRYSIZE);
objfile.symbols.Add(null);
i++;
}
}
}
public static Win32Obj readFromFile(String filename)
{
Win32Obj objfile = new Win32Obj(filename);
BinaryIn source = new BinaryIn(filename);
//coff header
objfile.machine = (MachineType)source.getTwo();
uint sectionCount = source.getTwo();
objfile.timeStamp = source.getFour();
uint symbolTblAddr = source.getFour();
uint symbolCount = source.getFour();
uint optionalHdrSize = source.getTwo();
objfile.characteristics = (int)source.getTwo();
//string tbl - follows symbol tbl
uint strtblpos = symbolTblAddr + symbolCount * CoffSymbol.SYMTBLENTRYSIZE;
source.seek(strtblpos);
byte[] strtbl = null;
uint len = source.getFour();
if (len > 4)
{
source.seek(strtblpos);
strtbl = source.getRange(len);
}
//section tbl
source.seek(COFFHDRSIZE);
for (int i = 0; i < sectionCount; i++)
{
//if section name is stored in string tbl, we read in index & let caller deref the actual name
String secname = source.getAsciiString(8);
if (secname[0] == '/')
{
int stridx = Int32.Parse(secname.Substring(1));
secname = readString(strtbl, stridx);
}
//read section hdr field
uint memSize = source.getFour(); //don't use - 0 in object files
uint memPos = source.getFour();
uint fileSize = source.getFour();
uint filePos = source.getFour();
uint relocPos = source.getFour();
uint lineNumPos = source.getFour(); //don't use - deprecated
uint relocCount = source.getTwo();
uint lineNumCount = source.getTwo(); //don't use
uint flagval = source.getFour();
SectionSettings settings = SectionSettings.decodeFlags(flagval);
CoffSection section = new CoffSection(secname, settings);
section.owner = objfile;
section.secNum = i + 1;
section.memPos = memPos;
section.fileSize = fileSize;
section.filePos = filePos;
section.relocTblPos = relocPos;
section.relocTblCount = relocCount;
objfile.sections.Add(section);
objfile.secNames[section.name] = section;
}
//load symbols
source.seek(symbolTblAddr);
loadSymbols(source, symbolCount, strtbl, objfile);
foreach (CoffSection section in objfile.sections)
{
//load section data
section.data = new List <Byte>(source.getRange(section.filePos, section.fileSize));
//load sectionrelocs
loadRelocations(source, section, objfile);
}
return(objfile);
}
